Friday, July 28, 2006

Crashing Into The Future

Welcome to the Moon. We hope your stay here is a pleasant one. Allow us to point out a few items of visual interest upon Lunar approach, for your touristing enjoyment. As we enter orbit, and then gradually slow to landing velocity so that we don't cut short your vacation by crashing into the Lunar surface, you may notice a few craters. Okay, you may notice a lot of craters. The reason being that lots of things that have come to land on the Moon have not slowed down upon approach, but have blasted their way into the surface of the Moon, leaving a permanent reminder of their brief but brilliant moment in Lunar history.

Imaginary tour over, back to reality. I saw a video a while back of some piece of flotsam striking the Moon with a rather satisfactory explosion. It was pretty, for a fraction of a second. Lots of comets and asteroids and such, wandering through space, have had an explosive and lasting impact on the Lunar surface. Did you know, however, that some of the things that have crashed into the Moon over the last few decades have been man made--and sent to collide there on purpose? According to NASA, dozens of spaceships have been intentionally crash-landed on the Moon:

NASA's first kamikazes were the Rangers, built and launched in the early 1960s. Five times, these car-sized spaceships plunged into the Moon, cameras clicking all the way down. They captured the first detailed images of lunar craters, then rocks and soil, then oblivion. Data beamed back to Earth about the Moon's surface were crucial to the success of later Apollo missions.

Even after NASA mastered soft landings, however, the crashing continued. In the late 1960s and early 70s, mission controllers routinely guided massive Saturn rocket boosters into the Moon to make the ground shake for Apollo seismometers. Crashing was much easier than orbiting, they discovered. The Moon's uneven gravity field tugs on satellites in strange ways, and without frequent course corrections, orbiters tend to veer into the ground. Thus the Moon became a convenient graveyard for old spaceships: All five of NASA's Lunar Orbiters (1966-1972), four Soviet Luna probes (1959-1965), two Apollo sub-satellites (1970-1971), Japan's Hiten spacecraft (1993) and NASA's Lunar Prospector (1999) ended up in craters of their own making.

This crashing thing has proven very useful, both as a way to ditch old spaceships and as a way to conduct experiments. So with such a time honored method of testing hypotheses at their disposal, the "crash it and see what happens" method, what's next? What do scientists want to try now? There are future trips to the Moon in the works; 2018 looms, when NASA wants to send humans back for another up close and personal look at the ball of green cheese that hangs in the night sky. So naturally, in the meantime, they're planning more of that always enjoyable pass-time, "Crashing for Fun and Profit", this time for the sake of important survival-in-space research. What they want to find out is whether there is water hiding in some of the frozen recesses in "the Moon's permanently-shadowed craters."

Water is pretty crucial to future success in establishing a permanent outpost anywhere in space, the Moon included:
The experiment couldn't be more important. NASA is returning to the Moon, and when explorers get there, they'll need water. Water can be split into hydrogen for rocket fuel and oxygen for breathing. It can be mixed with moondust to make concrete, a building material. Water makes an excellent radiation shield, and when you get thirsty you can drink it. One option is to ship water directly from Earth, but that's expensive. A better idea would be to mine water directly from the lunar soil.
The question is--is there water available to be mined? That's what they're hoping to find out with a project called LCROSS, Lunar CRater Observation and Sensing Satellite, scheduled for late 2008. The plan is to take two spacecraft and crash them into the Moon one after the other. The first ship will create an explosion and an accompanying debris cloud, the second will fly through the cloud, testing it for signs of water before it in turn meets its demise--all the while sending data back to Earth. They're even hoping that the debris plume from the double impact will be large enough to see from Earth, allowing observation to continue even after the second ship has fulfilled, and thus ended, its mission.

The task now is to try and pinpoint the best spot to crash and gather the resultant information. Scientists are debating the best possibilities: craters, canyons, lava tubes. They hope to find water deposited long ago by comets, and left frozen on the Moon. Since I'm not a proponent of the old Earth theory, I'm less sanguine about the concept that water will have been left by wandering water-bearers from long ago, but who knows what God has put there for us, knowing we would one day try venturing to the stars? However it got there, if it's there at all, it would be good if we can find it. After all, who wants to pack in water if they can find it locally? Camping 101. Camping on the Moon is going to have enough challenges; a local water source would be awfully helpful. I hope this crash test is a smashing success.